Technical Field
The invention relates to a touch control system and method, and more particularly, the invention relates to a control system and method for a capacitive touch screen.
Related Art
The principle behind capacitive touch screen sensing is applying a voltage to the touch sensing area and forming a uniform electric field, so that when the human body, such as a finger, touches the screen, the resulting capacitance variance induces a current after the transparent electrodes in the touch sensing area conduct in accordance with the weak current in the human body. By detecting the induced current with a touch screen controller, the touch coordinates can be calculated.
Currently, the touch coordinate feedback task of the touch screen controller can be implemented in a plurality of methods. One of the methods employs the touch analog front-end circuit to detect the capacitance variance of the capacitive touch screen, and uses the microcontroller (MCU) to compute the coordinates of the touch location. Computation of the touch coordinates by the MCU can be flexible since it allows for modifications to the computation method of the touch location by updating the firmware. However, this method places a high demand on the computational capability of the MCU, consumes more power, and the cost of the MCU configuration is relatively high.
Another method is complementing the touch analog front-end circuit with an exclusive hardware design for computing the touch coordinates. This method can increase the report rate and lower the power consumption. However, this method lacks flexibility since the touch computation equations used in the method are fixed, or the data flow in the computation are fixed.